Research Progress--Institute of Zoology Chinese Academy of Sciences

A jointed research by Prof. Zhibin Zhang (Co-corresponding author) from the Institute of Zoology, Chinese Academy of Sciences with Prof. Nils Stenseth (Co-corresponding author) and Leif Christian Stige (first author) from University of Oslo, Norway and other collaborators from Unites States and Switzerland reveals that The ecological effect of temperature on occurrences of migratory oriental locust may be frequency-dependent (Stige et al., 2007, PNAS). Previous study based on short time series data (about 50 yrs) demonstrates that summer locust occurrences are positively correlated to temperature of January (Ma et al., 1965). By using autoregressive model and spectral analysis, they re-analyzed the thousands-years locust data complied by Ma et al. (1958). They found locust occurrences were negatively correlated to temperature, indicating there were more locusts in cold phase than in warm phase. Because dryness is generally associated with cold phase, and wetness is associated with warm phase in China, a plausible explanation is that the more frequent droughts in cold phase benefits locust occurrences. Droughts and floods, esp. droughts, have been shown to be the key factor in triggering locust outbreaks (Ma et al., 1958). The significance of this new finding is that climate factors may have opposite low-frequency and high-frequency effects. Therefore, more attention needs to be paid to the frequency-dependent effect in studies of global climate biology. Since 1999, Zhibin Zhang and his colleagues have found population outbreaks of several agricultural pests in China, including migratory oriental locust (Zhang and Li 1999, Ecological Research) and Brandt’s vole (Zhang et al., 2003, Oikos), were well associated with El Nino and Southern Oscillation (ENSO). This new discovery again suggests that large-scale global climate factors are likely important to occurrences of biological disasters.